1. Field of the Invention
The invention relates to an apparatus for testing for the presence of trace amounts of a contraband material on a person.
2. Description of the Related Art
Terrorism risks continue to increase at transportation facilities, government buildings, banks, restaurants, hotels and other locations where there is a significant flow of pedestrian or vehicular traffic.
Airlines now routinely screen passengers and employees for explosives. Screening typically is carried out in several stages. For example, all passages are required to pass through a metal detector and all baggage is required to pass through an X-ray apparatus. However, a plastic explosive device could be concealed on a person or in a piece of luggage in a manner that might not be detected by a conventional metal detector or an X-ray apparatus. Even a small amount of a plastic explosive can cause sufficient damage to bring down an aircraft.
Most airports now include apparatus for detecting trace amounts of explosives. These devices operate on the principle that small amounts of the explosive materials will be transferred to the body, clothing and luggage of people who had handled the explosive. Some detectors employ small flexible fabric-like traps that can be wiped across a package or piece of luggage. The trap removes residue from the surface of the package or luggage. The trap then is placed in an apparatus, such as an ion trap mobility spectrometer, that tests the residue on the trap for trace amounts of explosive materials. A device of this type is disclosed in U.S. Pat. No. 5,491,337 and is marketed by the GE Ion Track. These devices typically are employed in proximity to the metal detectors, and security personnel will perform screening on some of the passengers based on a random sampling or based on a determination that the passenger has met certain criteria for enhanced screening.
The ion trap mobility spectrometer disclosed in U.S. Pat. No. 5,491,337 also can operate in a mode for detecting trace amounts of narcotics. Narcotics are illegal and insidious. Furthermore, it is known that many terrorists organizations fund their terrorism through the lucrative sale of narcotics.
The above-described ion trap mobility spectrometer and similar devices have been accepted at airports in view of the notorious efforts of terrorist groups to attack commercial airliners. The above-described detectors have not been accepted widely at other potential targets of terrorism, including train stations, bus terminals, government buildings and the like. The screening of personnel entering train stations, bus depots, government buildings and such by the above-described detection devices would significantly slow the flow of people into and through such buildings and would impose a significant cost penalty on the operators of such facilities.
Only a fraction of airline passengers have their baggage checked for trace amounts of explosives or narcotics using the available ion trap mobility spectrometers and similar devices. Efforts to use such devices to check all bags for trace amounts of explosives or narcotics would impose greater time and cost penalties on the airline industry. Additionally, explosive detectors typically are used only on luggage and other parcels. An apparatus of this type would not identify plastic explosives worn by a passenger who had no carry-on luggage.
U.S. Pat. No. 6,073,499 discloses a walk-through detector. The detector shown in U.S. Pat. No. 6,073,499 operates under the principle that a boundary layer of air adjacent to a person is heated by the person. This heated air adjacent a person is less dense than air further from the person. Less dense air rises. Accordingly, a thermal plume of air flows up adjacent to a person. Minute particles, including particles of explosives or narcotics, will be entrained in this thermal plume of air and will flow upwardly from a person. The walk-through detector disclosed in U.S. Pat. No. 6,073,499 employs an ion mobility spectrometer or ion trap mobility spectrometer to detect microscopic particles of interest that are likely to be entrained in the thermal plume of air flowing upwardly adjacent to a person who walks through and pauses briefly in the detector. The walk-through detector disclosed in U.S. Pat. No. 6,073,499 is very effective for detecting whether a person is carrying explosives or narcotics and whether the person has recently handled explosives or narcotics.
A person who had handled explosives or narcotics is likely to have microscopic residue of the explosive or narcotic materials on his or her fingers, and trace amounts of the explosive or narcotic will be transferred to objects that are handled by the person. U.S. Pat. No. 5,741,984 discloses an apparatus for dispensing tokens that preferably are made of PTFE or cotton. The dispensing apparatus is constructed so that the individual is required to grip the token tightly to separate the token from the dispensing apparatus. The token then is fed into a token handler that delivers the token into an ion mobility spectrometer for analyzing residue that may have been transferred to the token from the hand of the person who retrieved the token from the dispenser. The apparatus shown in U.S. Pat. No. 5,741,984 creates inventory control problems associated with the need for having a sufficient supply of tokens and then periodically loading tokens into the dispenser. Additionally, the system disclosed in U.S. Pat. No. 5,741,984 requires a separate complex dispensing apparatus for dispensing tokens with sufficient resistance for reliably transferring residue from the hand of the person retrieving the token. Additionally, a complex apparatus is required for handling the token, feeding the token into the ion mobility spectrometer and then removing the token after analysis. The inventor of the subject application has determined that residue of such contraband will be transferred from the fingers of the person to an airline ticket, a boarding pass or an identification card. Pending U.S. patent application Ser. No. 10/774,003 discloses a detector that identifies particles of interest on such a card-like object. Accordingly, the device disclosed in pending U.S. patent application Ser. No. 10/774,003 avoids problems associated with maintaining an inventory of tokens, dispensing tokens properly from a dispenser, handling tokens in a token handler and then removing the tokens from the token handler.
The above-described products that check for the presence of trace amounts of substance of interest on luggage, tickets, boarding passes and the like generally work very well. However, there continues to be a demand for a small, rapid, reliable and low cost detector for detecting trace amounts of substances of interest directly on a person. A device of this type would be useful at security checkpoints where a person is not likely to be carrying luggage (e.g., many commuter train stations or bus terminals) and at locations where a person is not likely to have a boarding pass (e.g., government buildings). The above-described walk-through portal provides an unobtrusive checking of passengers for explosives or narcotics without the need to check luggage or boarding passes. However, these devices are relatively large and relatively costly. Hence, devices of this type may be inappropriate for some security checkpoints.
Existing security checkpoints also are very labor intensive, and devices that could reduce the number of highly trained technicians would be received favorably. In this regard, a typical airport security checkpoint requires at least four and typically five or six trained technicians. A first employee reviews personal identification cards and boarding passes at the entry to the checkpoint. A second person coordinates the loading of carry-on luggage and personal effects onto a conveyor for movement through an X-ray scanning device. A third person continuously watches the monitor of the X-ray scanning device. A fourth person controls the movement of passengers through the walk-through metal detector while a fifth person remains available for conducting more detailed screening with a handheld metal detector. The above-described explosive/narcotics detection device that employs fabric-like wipes typically is positioned near the outlet end of the conveyor through the X-ray scanning device. As noted above, the small fabric-like trap is wiped across the surface of the luggage to pick up trace amounts of substances of interest that may have been transferred from the passenger to the luggage. The wipes then are placed in the detector and analyzed. A sixth technician generally is available to perform this screening and analysis. Alternatively one of the five technicians mentioned above must be redeployed for this screening and analysis. A more direct approach would be to detect the substances of interest directly on the passenger. Most preferably, such detection would be carried out without direct human intervention by the technicians who operate the checkpoint.
It is assumed that terrorists and other criminals frequently travel without carrying explosives, weapons or other contraband. Existing security checks at airports compare the name on a boarding pass to the name on a photo identification card and then compare the passenger to the photograph. However, there is virtually no checking of the physical characteristics of the passenger to physical characteristics of suspected terrorists and criminals. Additionally, there is virtually no checking of physical characteristics of the passenger to documented physical characteristics of the person whose name appears on the boarding pass or photographic identification. There is also no checking of whether a person with the physical characteristics of the passenger has traveled previously under a different name.
Devices are available for taking fingerprints of a person and for comparing the fingerprints to information in a database of fingerprint information. Such an apparatus can compare a scanned fingerprint to fingerprints of certain known suspects. Such an apparatus also can store fingerprint data for future reference or analysis. Other apparatus can identify people by scans of facial features or other characteristics.
Accordingly, an object of the subject invention is to provide a device for detecting the presence of substance of interest on a person at a security checkpoint.
Another object of the invention is to provide a device that can check for the presence of a substance of interest without intrusion on the passenger by security personnel.
A further object of the subject invention is to provide an apparatus that can substantially simultaneously check for the presence of a substance of interest and check the identity of the person at the security checkpoint.
An additional object of the invention is to provide a lightweight relatively, low cost, small apparatus for checking for the presence of substances of interest on a person.
Still a further object of the invention is to provide a sampling apparatus where the sampling medium is reusable and non-removably part of the sampling apparatus.